This isn't an intentional design decision, it comes from a lack of understanding of the issue which was originally present in CPM. Additionally, in the current state of the movement system the player in the air can't escape a rocket bounce with simply A/D anyway (partly because rocket bounces are broken as fuck right now but that's besides the point). Making W/S consistent with A/D would not change anything at all in that situation. On the other hand being able to bunny hop sideways, for example, would add another level of mastery to the movement.

I always play on lowest anyway. Its like lights just come out of where the beam hits a player and fill your screen will screenshot sometime later d.maxfile.ro/hidigcfmjv.png Taken from a video but you get the point